1. Technical Field
The present invention relates to a positioning method, a program, a positioning device, and an electronic apparatus.
2. Related Art
A GPS (global positioning system) is widely known as a positioning system using a satellite and is used in a positioning device built in a mobile phone, a car navigation apparatus, and the like. The GPS measures its current position by executing a positioning operation for calculating four parameter values of three-dimensional coordinate values, which indicate the position of the GPS, and a time error on the basis of information, such as the positions of a plurality of GPS satellites or a pseudo distance from each GPS satellite to the GPS.
However, in the positioning using a GPS, it is difficult to avoid generation of a positioning error because there are various kinds of error factors, such as multipath influence. For this reason, various techniques for reducing the positioning error have been proposed. As an example, a technique related to positioning processing using a Kalman filter is disclosed in JP-A-2001-337156.
In positioning processing using the Kalman filter, positioning is performed by repeating a procedure of measuring the current position by predicting a relative movement distance from a measured position before 1 time, but it is necessary to set an initial position first. In the technique disclosed in JP-A-2001-337156, for example, a measured position obtained in positioning processing using a least square method is set as the initial position.
However, in the case where the measured position obtained in the positioning processing using the least square method largely deviates from the true position of the positioning device, there has been a problem that the positioning accuracy lowers in the positioning processing using the Kalman filter because the measured position is calculated by predicting the relative movement distance from the largely deviating position.